Im Not sure but somethings is differant

I replaced the stock Air filter with a UNI.

Since then I do nt need to start the bike Cold with the choke.

If I try when cold, I get one Pop then its kick kick kick.

I set the Hot Start Fires right up.

I just put the bike back together started it with no Choke, stone cold bike, In fact It had not been started in 10 days


Im not complaining, I just can not believe a filter would do this.

I just cleaned the Carb and put it back, adjusted everythng.

i can only account is that now my 45 pilot is to rich, But when its running Bamm no problems

[ July 28, 2002: Message edited by: E.G.O.**** ]

uni filters and other dual stage filters restrict more air, causing a self-choking is not enough, however, to cause any jettingchanges while running. thats my theory.



I run an UNI filter

MJ = 162

PJ = 42

F-Screw 1-1/2 turns

Needle = EKP clip 4 ?

Elevation = 1000'

its 95 deg. dew point 75 deg. humidity 75+

SUNOCO Purple 110 pump octaine

My YZ runs good maybe a hair rich



I am not sure about your description on dual stage. I was loking at that, You may be right though, I suspect that I may have to go back to the 42 pilot. But I thnk what is going on is the Filter is allowing it to breath cleaner, so the effect would be too rich e\becouse of the 45 pilot I had to place in it.

Thats my thoery, I may just clean the peepee out of the original and swap it just for a stupid butt test.

Unka Rich

Thanks I think I will probably go back to the 42, I will be intrested to see how the beast runs on Tuesday with the 168 main...

How long did you wait after oiling the filter? It takes a couple hours for all the solvents to evaporate. All my YZF's do exactly what your describing with freshly oiled filters and will in fact refuse to start at all. Wait overnight, and you can't tell one filter from another, and no jetting changes required for stock, uni, or twinair filters. Once you have sucked filter oil into the tiny carb air passages, you could could experience long-lasting carb problems until you clean it out. Moral of the story: Never start your YZF with a freshly oiled filter.


'03 YZF450 (on the way)

'01 YZF250 (for sale)

'99 YZF400

'98 YZF400

OK Geez why did not I think of the Oil Thingy thing

Man I am so dumb, thanks for the advise


I dont think I ever started my bike for at least a day or so after oiling the filter, you may be on to something

Thanks for the tip


Shawn MC, thats exactly what I think happened to me. Oiled the filter, paper towel dried it, let it sit for a day even. Next time bike barely started only with the choke on whole time. Pulled carb and the PJ had something stuck at the end, completely clogged there. Contact Cleaner did almost nothing, had to shave a tooth pick and poke it out, everything else was good though in there.

Pray you didnt pull oil into the pilot passage. Especially if its has sat over night. Nice sticky fully dried filter oil in those little tiny passages. Get ready to buy a couple cans of contact cleaner, it works pretty good on that stuff.

Good luck bud


86 db 98 db, loud stinking Wobbly Ablesons,

DWF = Dual Wife Syndrom,

Now its Oil in Me carb

Im gonna move to a small town and die

WAIT I live in a small town



Man talk about getting hit by caffiene that was a rush

Got it covered shawn, thanks though

[ July 29, 2002: Message edited by: E.G.O.**** ]

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